Final answer:
Mathematical models and resources, such as the NPK rating system, can be used to determine the nutrient requirements of plants. Studies on soil fertility and climatic characteristics also provide valuable information in this regard.
Step-by-step explanation:
To determine the nutrient requirements of plants, mathematical models and resources can be utilized. One important mathematical model is the NPK rating system, which describes the amount of nitrogen, phosphorus, and potassium in a fertilizer. This rating system is used to formulate fertilizers that provide the necessary nutrients for plant growth. Other resources that can aid in determining nutrient requirements include studies on soil fertility and climatic characteristics, which provide information on the availability and uptake of nutrients by plants.